Drill



mmm

H. P. GERDIL' DRILL FiledwJune 23, 1920 INVENTOR Henn Prosper GerdvL ByATTORNEY.

Patented May is, was.

i g 'Svlilg 7 nnnarrnosrnn Gnnnrn, on PARIS, FRANCE."

DRILL.

Appiieation ined rane 2a, i920. serial no aeigoza To all whom At mayconcern:

` Be -it known that l, HENRI Pnosrnn GERDIL, citizen of the Republic ofFrance, residing at 5l Avenue de Sutlren, Paris, in the Republic otFrance, have invented new andr useful Improvements in Drills, of whichthe vfollowing is a. specification.

y This invention relates to improvements in cutting or. non-'cuttingtools used for working any materials.

ln his patent application No. 317,139, applicant has described a rot-arycutting tool characterized in that it is provided withvbeari-ngvsurfaces of a reduced area which are preferably in the form ofthin ribs and by means of which the tool may rest diiiingtlie operation.upon the wall of the -vcut formed in the work.`

. Applicant has also described in the above application animprovement'in rotary cutting tools which consists inthat lthe pitch jor angular `distance between two succeeding .cutting edges is greaterthan or equal to the l arc along which each cutting edge can engage withthe work, whereby the tool never has two or more cutting edges inengagement v with thev work at the same time.

v of example This invent-ion consists in extending vsaid improvementstothat kindof tools which are ln the case of tools working axially, i.e.,

the end workwith a feed along the axis otrotation, such.

as drills. etc., the .working end ofthe tool can be ribbed in .variouswave. The drill which is represented in riigs. l, 2 and 3 is .y

provided with a bevelled cutting `edgeI ll. The arcalongv which the toolis in engage` ment with tlie yv-:ork being 360. one cutting edge only isprovided. 'Two ribs 12 of Athe radial type are provided. said ribstorming the continuation oi' the lateral ribs provided on the sidesurface ot the'tool and extending the three following cases: g y l l.The vwork isv stationaryand the'tool is along the' linev up to thecentral point of the drill. `The top l' 'faces of said end ribs arekuniformly dis-l tributed on the conical surface containing the cutting`edge. vTo Jform said ribs, the

able places.- f f y The drillwhich is end of the tool hasbeen` hollowedin lsuit-l represented in Figs. et

and 5 is provided with a bevelled cutting edge `shown at 13. The-rib,which is of the concentric type, is merely formed by a small centralcapl or projection 14C lhavinga few millimeters in diameter; The cuttingedge,v

the capl and the end surfaceof thetoolhave the conicity. The cap l4projects above theend surface or' the tool by the same distance as thecutting edge.4 The central `cap forms a pivot which acts to hold thetool.

Finally., the invention consists also in apr.

plying the improvements described in thev prior application abovereferred to, kas well atthose explained above whatever be the Way inwhich the relative movement between the".v

tool and the work is obtained, viz. in anyone movable,"

' 2. The work is movablel and vthe`tool.isy

stationary, 3. The work taneously. Y l

Having now described myv invention, what l claim vas new and desire tosecure by Let-V and the tool are moved simulters Patent is:

f 1.' drilly comprising a main body, :if vsingle radial cutting edge onthe end working face of said body, thin longitudinal ribs guiding thedrill in the hole formed in the work and thin radial ribs on said endWorking face in the plane `of said longitudinal ribs bottom) wall of thehole formed inthework.

' 2. A `drill comprising a main body,` a`

single radial cutting edge projecting' above the end worring face ofsaid body, thin longitudinal ribs guiding the drill in the hole formedinthe work and la small central cap on said end Working face "projectingabove the latter by thevs'ame distance asthe i yand adapted to rest inoperation upon' the cutting ede and adapted to rest in operation uponthe bottoni wall of the Vhole formed in the work.

ln testimony'whereoli l `have signedmy rname to this specification.

Hanni Pnosrnn'ennnin

